Field of the Invention
The present disclosure relates to catheters. In more particular, the present invention relates to a catheter having a radiopaque marker adapted to allow a practitioner to simply and efficiently identify the precise location of a predetermined drainage bore located on a catheter that is positioned within a patient.
Relevant Technology
One of the important therapeutic tools in modern medicine relates to the removal of volumes of fluids from a predetermined location within a patient's body. Fluids that collect in a patient's tissue, body cavities, or other positions within the patient's body, and which exceed normal volumes can contribute to infection, exert potentially harmful pressure on the patient's organs, or otherwise impede in the proper care and recovery of a patient. Drainage catheters have long been utilized to drain such excess volumes of fluids from a patient's body. Typically, the drainage catheter is adapted to be introduced into the patient at the site where the excess fluid is accumulated. A plurality of drainage bores are positioned in a distal end of the catheter to allow the passage of the fluids and any materials suspended in the fluids from the volume of fluid to the lumen of the catheter.
The distal end of drainage catheters are typically adapted to form an anchor configuration to secure the drainage catheter at the site where excess fluid is accumulated. However, the tissue surrounding drainage sites often does not provide a solid or reliable substrate to maintain the position of the catheter within the patient. As a result, the anchor configuration of the catheter is typically formed in a relatively large pigtail type loop that provides a reliable anchor regardless of the characteristics of the surrounding tissue. The pigtail loop is formed by securing the tip of the catheter tube such that the tip of the catheter contacts a more proximal position on the catheter tube. This is accomplished by utilizing a suture that is threaded between the proximal position and the tip of the catheter. The suture is adapted to run the length of the catheter and exit the catheter at the proximal end of the catheter tube. This allows the user to manipulate the suture to maintain or release the anchor configuration of the distal end of the catheter while the distal end of the catheter is positioned inside the patient.
A problem associated with inserting and properly anchoring a drainage catheter within a patient relates to identifying the disposition of the bore holes within a patient and determining that the catheter has been advanced to the desired location within the patient such that it can be anchored within a target cavity or tissue within the patient. A practitioner will typically advance the drainage portion of the catheter until all bore holes of the catheter are disposed within the cavity to be drained of fluid. This avoids accidental drainage of fluid out of one body cavity or locale within the patient and into another cavity or tissue, rather than being drained from the cavity to outside the patient.
Traditionally, radiopaque markers have been used in conjunction with X-ray radiography to determine the location of a distal end of a catheter within the patient. Radiographic techniques utilize imaging techniques to visualize internal patient structures and/or objects within a patient. The term “imaging techniques” is generically used. Examples of imaging techniques include X-ray radiography to identify both the technique of projection radiography using X-ray radiation and the resulting image, which may be on film or captured digitally and viewed via an electronic medium. Other radiographic techniques include Fluorography and Computed Tomography scan (CT or CAT scan). Additional imaging techniques subsumed within the term do not use X-rays but may still be useful for identifying the position of a catheter with a radiopaque marker within a patient. Such techniques may include ultrasound, and Magnetic Resonance Imaging (MRI), although MRI may be contraindicated for use with some types of radiopaque markers.
Conventionally, radiopaque markers are metallic pieces disposed at a given position on a drainage catheter to allow a practitioner to identify the position of the catheter within the patient. As their name implies, radiopaque markers at least partially block X-rays and so that the marker can be clearly distinguished via radiography from patient tissues surrounding the marker. This allows for ready appreciation of the approximate location of the bore holes within the patient.
There are a number of deficiencies of the traditional metal bands comprising typical radiopaque markers. Such metal bands may become loosened from the catheter tube such that they can rotate around the tube or even possibly slide up and down the tube. The possibility of the marker band being displaced from its predetermined position is a significant problem with traditional bands. Movement of a marker band can be particularly problematic to the extent that the location of the distal end of the catheter tube may no longer be indicated by the maker. An additional problem relates to the fact that it is difficult to align the metal bands with drainage bores of the catheter. For example, punching holes through both the metal radiopaque marker band and the elastomeric catheter can result in damage to one or both of the radiopaque marker band and the catheter. This is due to the hardness of the marker band and the softness of the catheter tube.
Attempts to align preformed drainage bores in the marker band and the catheter tube can be difficult or impractical. Additionally, inadvertent rotation of the band around the tube may cause a bore hole present in the band to become misaligned with a bore hole in the tube, thereby reducing the ability of the catheter to drain fluid. As a result, marker bands are positioned either distally or proximally with relation to the drainage apertures. However, slipping of the marker band can lead to miscalculations of the orientation of the marker bands to the drainage apertures. In some circumstances, the marker band can even inadvertently obstruct a drainage bore of the catheter. Even where the marker band does not slip, the practitioner is required to make estimations of the actual location of a particular drainage bore relative to the marker band.
Another difficulty relates to the fact that inclusion of the marker band on the catheter tube can increase the outer diameter of the catheter tube or require special processing to minimize any increase in the diameter of the catheter tube. In some cases, an undesirable ridge or other profile is created which can interfere with normal operation of the catheter. A variety of complicated assembly techniques have been developed to secure marker bands between multiple wall layers of catheter tubes. These techniques can require complex machinery, assembly and cost. Additionally, such techniques do not lend themselves to the positioning of a drainage bore contiguous with the marker band.